Unveiling Large Magnetic Exchange Coupling and Intermolecular Interactions in Diverse Carbon-Based Nanomaterials

Carbon-based nanostructures have emerged as promising candidates in spintronic and quantum technology applications due to their fascinating electronic and magnetic properties. Dispersed carbon-based nanostructures, such as 0D motifs, 1D chains, and 2D networks, are accessible through the versatile protocol of on-surface synthesis, overcoming the limitations of traditional synthetic methods.1 Leveraging this capability, a variety of open-shell carbon nanostructures, including 0D nanographenes and 1D molecular chains, can be synthesized with tunable magnetic properties, thereby creating a diverse range of magnetic systems complementing the library of π-magnets fabricated via on-surface chemistry approaches.2

A crucial parameter in magnetic materials is the magnetic exchange coupling (MEC) between unpaired spins, which must be large enough to enable device operation at practical temperatures. In this talk, we focus on specific 0D nanographenes and 1D π-conjugated polymers that lead to the generation of unpaired spins. Notably, an impressive magnetic exchange coupling of 190 meV and 180 meV is observed in an all-benzenoid framework3 and in an azulene-embedded nanographene species4,respectively, representing the highest magnetic exchange coupling reported for both benzenoid and non-benzenoid carbon-based structures on surfaces to date. These structures have been precisely synthesized and finely characterized by virtue of on-surface synthesis strategy and scanning probe microscopy (SPM) techniques. On the other hand, as the dimension of carbon-based nanostructures extends to 1D π-conjugated polymers, many intriguing nanomaterials emerge with fascinating physicochemical properties. In the second part, we will explore the structural and electronic properties of 1D carbon-based nanostructures probed by SPM.

References

[1] Zhang, Chi, et al. Materials Futures 1.3 (2022): 032301.

[2] de Oteyza, Dimas G, et al. Journal of Physics: Condensed Matter 34.44 (2022): 443001.

[3] Biswas, K, et al. Journal of the American Chemical Society 145.5 (2023): 2968-2974

[4] Biswas, K, et al.  Angewandte Chemie 136.13 (2024): e202318185.

[5] Biswas, K, et al. Journal of the American Chemical Society 144.28 (2022): 12725-12731.